The election was precipitated by a lost vote of confidence for the ruling Labour government under Jim Callaghan. The Labour government had been in power from February 1974, with Callaghan succeeding Harold Wilson in April 1976. The administration had been a minority government for most of its term, from March 1977 to August 1978 the government was forced into a Lib-Lab Pact in order to retain power. The government held out through the end of 1978 hoping to see improvements in the economy, what they got was the Winter of discontent. When the SNP withdrew support there was a vote of no confidence, which passed on March 28, 1979, forcing an election to be called.
Margaret Thatcher had come to head her party in 1975, replacing Edward Heath (to his eternal annoyance). The Conservatives campaigned on economic issues - promising to comtrol inflation and check the unions, hoping to downplay the high personal unpopularity of their leader. They also called on the advertising agency Saatchi and Saatchi to help with their campaign.
A Conservative victory had seemed almost certain, the overall swing of 5.2% was the largest since 1945 and gave the Conservatives a workable majority of 43 for the country's first woman Prime Minister.
| Party | Votes | Seats | Loss/Gain | Share of Vote (%) |
| Conservative | 13,697,923 | 339 | + 62 | 43.9 |
| Labour | 11,532,218 | 269 | - 50 | 36.9 |
| Liberal | 4,313,804 | 11 | - 2 | 13.8 |
| Others | 1,677,417 | 16 | - 10 | 5.4 |